Theresa Mintle, a distant cousin of former Mayor Richard M. Daley, is resigning effective March 15 after 22 months as the hard-charging mayor’s first chief of staff and 26 years in government. Mintle, 48, “feels like the administration and the team is in the right place for her to resign,” said Sarah Hamilton, the mayor’s spokeswoman.

Mintle will be replaced by Lisa Schrader, the chief operating officer who worked for Daley for 10 years before Emanuel took office and promoted her. Schrader, 41, started at the city as a budget spokeswoman and worked her way up to deputy chief of staff at the end of the Daley era.

Schrader previously worked for the Democratic National Committee and on political and issue campaigns. As chief operating officer, she has been managing city operations and coordinating efforts with agencies like the CTA, Chicago Public Schools and Chicago Park District.

“With nearly two decades of experience working in city government, politics and the private sector, Lisa has the experience necessary to manage the day-to-day activities of city government,” Emanuel said in a statement.

When Emanuel informed his senior staff of the change Thursday morning, he praised Mintle, Hamilton said. Mintle, whose father died recently, had been considering retiring from government service to recharge even before taking the top job under Emanuel, she said.